uniq

Problem

You need to deduplicate an array, optionally by a computed key rather than full object equality.

Solution

Use uniq(array, selector?) to return a new array with duplicate values removed.

import { uniq } from '@vielzeug/arsenal';

uniq([1, 2, 2, 3, 1]);
// [1, 2, 3]

const users = [
  { id: 1, name: 'Alice' },
  { id: 2, name: 'Bob' },
  { id: 1, name: 'Alice (dup)' },
];
uniq(users, (u) => u.id);
// [{ id: 1, name: 'Alice' }, { id: 2, name: 'Bob' }]

Pitfalls

• Without a selector, uses deep equality — use a selector for object arrays to avoid expensive deep comparisons.
• First occurrence wins when duplicates are found.

Related

• union
• compact